Collared Delma Habitat Enhancement

Improving Collared Delma trajectories in Brisbane’s western suburbs

The project Improving Collared Delma trajectories in Brisbane’s western suburbs was jointly implemented by Pullen Pullen and Kholo Creek Catchments groups from April 2022 to March 2023. It was supported by funding from the Australian Government.

The Collared Delma (Delma torquata) is a small legless lizard currently on the Priority Species list under the Australian Government’s Threatened Species Strategy. It inhabits open eucalypt forest with grassy understory and one of its remaining strongholds is in the western suburbs of Brisbane. However its capacity to survive in these areas is far from certain; it faces numerous threats including changing patterns of land use, invasive weeds such as Creeping Lantana (Lantana montevidensis) and predation by domestic pets such as cats and chickens.

The project sought to improve its trajectories and extend knowledge about its distribution through surveys to record its presence, weed management and habitat augmentation. Twenty-two local landholders offered their properties for assessment and the Brisbane City Council gave permission for habitat enhancement in a section of Anstead Bushland Reserve (a known Collared Delma site).

Assessment of the private properties was guided by a Collared Delma habitat assessment screening tool developed by the team from information on previous sightings, advice from Collared Delma experts and observations of co-existing species. This proved invaluable for the project for ranking the properties in terms of the suitable habitat and will be an important resource for future projects and expanding knowledge about Collared Delma habitat.

Surveys for Collared Delma populations were undertaken in 20 properties. Two new confirmed sightings were made, unsurprisingly in the highest ranked properties. Information on the properties surveyed and the 25 other reptile species recorded are presented in our Collared Delma Survey Report which is another major resource produced by the project that contributes to the expansion of knowledge about this species.

A primary goal of the project was to enhance habitat for the Collared Delma and to this end considerable effort was devoted to the removal of invasive weeds from areas of potential habitat. Two contractors (Bushtekniq and Oxley Creek Catchment Association) were hired to undertake this sensitive work, which was conducted without the use of herbicides or heavy machinery, rather relying on labour intensive hand weeding techniques. This was essential to avoid damage to any reptiles inhabiting the areas or their food sources.

The transformation in these sites was remarkable, particularly in properties where Creeping Lantana was rampant. Maintenance over the longer term is now imperative!

In addition to weed management, habitat augmentation (the placement of rocks on the ground along with mulch and planting native grasses or scattering locally collected grass seeds) took place in several sites after weeding. This extended habitat for the Collared Delma when it was done alongside existing habitat and provided greater protection for the species in areas that were exposed after weeding.

Another important goal of the project was to increase knowledge and community awareness of the Collared Delma and its vulnerability. In addition to one-on-one onsite interactions with landholders over the course of the project, a major contribution to these goals was a Community Workshop held in February 2023. The Workshop attracted over 60 people, with activities including presentations on the Collared Delma, demonstration of habitat restoration in progress and free take-aways including documentation on caring for Collared Delma habitat, plants suitable for enhancing habitat and booklet on local ground covers  produced by an expert member of the project team.

Overall the project contributed to improving Collared Delma trajectories by enhancing habitat and educating landholders and the local community about weed control and habitat maintenance. The surveys conducted provide a baseline for follow-up research in these sites and the habitat assessment tool will be invaluable for future projects. We hope to be reporting habitat improvements and an increasing number of Collared Delma sightings in the years to come!